A traditional Windows, Icons, Menus, Pointer (WIMP) device may offer a mouse pointer, left and right mouse buttons, a scroll wheel, keyboard scroll keys, and keyboard modifiers. A touchscreen device, on the other hand, generally relies on touch on the screen to send commands to the system. However, in some cases, the underlying touch system is similar to the WIMP system and requires similar control information.
There is typically no equivalent for hover events (e.g., mouseover events and/or mouseout events) on touchscreen devices. For example, this can be problematic for touchscreen browsers, since hovering may be provided for by languages such as Javascript, HTML, and Cascading Style Sheet (CSS). Websites may use mouseover and/or mouseout events for various certain objects (e.g. menu opens on hover, content is displayed on hover), but pressing on the touchscreen may be ambiguous as it is unclear whether the user is tapping or hovering over the object. In general, a press on the displayed object is treated as a regular mouseclick event (e.g., jumping to another page).